Reversible engine control apparatus



y 1951 R. T. WHITNEY 2,558,891

REVERSIBLE ENGINE CONTROL APPARATUS Filed July 27, 1949 I1 .1 '4wReversible 5 7/ Engine Crank Sheff rllh ZOO 'Z'LIE' 10o 5 Z) 1 6 6Reversible .72 '72: Engine Crank Sheff INVEN TOR.

BY aphTZMmney P atented July 3, 1951 REVERSIBLE ENGINE CONTROL APPARATUSRalph T. Whitney, Irwin, Pa., assignor to The Westinghouse Air BrakeCompany, Wilmerding,

Pa., a corporation of Pennsylvania 6 Claims. 1

This invention relates to control apparatus and more particularly tocontrol apparatus for reversible engines. 7

In certain control apparatus for reversible engines a direction sensingdevice is employed which, in the usual form, comprises a friction shoefor actuation into friction contact with a rotating crank shaft of areversible engine to sense the direction of rotation of same throughresultant movement in a corresponding direction to condition certainvalve mechanism accordingly.

In such a direction sensing device, the above mentioned friction shoe ismoved into sliding frictional engagement with the rotating crank shaftby operation of fluid pressure piston means and held in such slidingengagement for considerable time at the expense of wear on the shoe.

It is a prime object of the present invention to provide an improveddirection sensing device for sensing direction of rotation of such as areversible engine crank shaft which comprises improved means forconditioning the valve mechanism therein.

Other objects and advantages will become apparent from the followingmore detailed description of the invention.

In the accompanying drawing; Fig. l is a schematic view substantially insection of a direction sensing device embodying the invention; and Figs.2 and 3 are respective modifications of a portion of the device shown inFig. 1.

Description Referring to Fig. l, the valve portion of the directionsensing device may comprise, in the usual form, a casing adapted to bemounted in a fixed position relative to a reversible engine and eitheron or immediately adjacent thereto. The casing usually encloses twopoppet valves I and 2 contained in chambers 3 and 4 respectively, whichchambers are open to such as forward and reverse control pipes I and200, respectively. The poppet valves I and 2 are arranged side by sidewith parallel extending fluted stems 5 and 6, respectively, which stemsextend into a chamber I common to both and connected to such as a pipe300. The valves I and 2 control communication between the chamber I andthe chambers 3, 4 respectively, hence between the pipe 300 and theforward and reverse control pipes I00 and 200, respectively. A spring 8in each of the chambers 3 and 4 acts on the respective valve I, 2 tourge sametoward a'closed position, in which position the valve I isshown in the drawing.

7 Application July 27, 1949, Serial No. 106,995

The valve stems 5 and 6 are'adapted to be engaged by two spaced apartoperating plungers 9 and II], respectively, which are slidably mountedin the casing and provided with stems II and I 2" which extend outwardlythrough said casing.- Two rockable cams I4 and I5, fulcrumed on pinssecured in the casing, are provided for actuating the stems II and I2,respectively, and thereby the valves I and 2, respectively. These camsmay be identical, but reversely arranged, and each is operativelyconnected to the respective plunger I I, I2 through the medium of afollower element I! which is rockably mounted on a pin secured in thecasing. Each of the cams I4 and I5 is provided with a surface I9, which,when'in ngagement with the respective element I1, will unseat therespective valve I or 2. Adjacent to the surface I9, each cam isprovided with a recess 20 which recess is adapted to receive therespective element I! to permit movement of'the respective plunger 9 orID by a spring 2I to a position disposed away from stems 5 or 6 topermit closure of the respective valve I or 2 by the respective spring8.

The two cams I4 and I5 are operatively connected for movement in unisonby a link 22, and since the cams are reversed as above mentioned,movement of the link and cams to the position in which they are shown inthe drawing will effect opening of the valve 2 and closing of the; valveI, while movement of said link and cams in a clockwise direction, asviewed in the drawing, to a position in which the surface I9 on the cam-I4 engages the respective element I! will effect opening of the valve Iand closing of thevalve 2.

According to a feature of the invention, in lieu of the usual frictionshoe for sliding fric tional engagement with such as the outer surfaceof an engine crank shaft to actuate the valve mechanism, I provide acontact element 30 for rolling engagement with the engine crank shaft orwith an element secured to rotate with the crank shaft.

In Fig. l, the contact element 30 may be in the form of a segmentalpinion 30 adaptedfor pivotal movement about a pin 3| secured to thecasing between two opposite disengaged positions and during suchmovement into and out of engagement with teeth or serrations formed onthe peripheral surface of a gear or similar element 32 which may beformed integral with or be re movably attached to such as the enginecranlr shaft designated in the drawing by an appropriate legend. Thecontact e1e'ment'30is connected to the pin 3| through the medium of anarm 33 which arm is operatively connected to the link 22 for actuatingthe valves I and 2 by a link 34, which link 34 is connected at its oneend to said arm by a pin 35 (Fig. 2) and to said link 22 at its oppositeend by a pin 36. The valves I and 2, cams I4 and I5, links 22 and 34,arm 33, and element 30 are held in the position in which they areshown'in Fig. 1 by action of a tension toggle spring 31 which is pinconnected at its opposite ends to the casing by a pin 38 and to the armby a pin 39. Such position of the above elements is defined by contactof the element 30 with the projecting end of a piston rod 40 which isoperatively attached to an actuating piston 4| shown in the drawing in arepose position, with said element 30 disposed away from the gear 32 atthis time. In a position opposite to that in which it is shown in thedrawing, the contact element 30 will be held by spring 31 in contactwith a similar piston rod 42 attached to an actuating piston 43 whichwill then be in its repose position in which it is shown in the drawing,and the links 34 and 22 and cams I4 and I will be so positioned, aspreviously described, that the valve I will beopen and the valve 2closed with the chamber I, hence pipe 300, closed to the chamber 4,hence pipe 200, and open to chamber 3, hence to the pipe I00. The spring31 will act to hold the parts of the device in the above definedrespective positions.

The pistons 4| and 43 are slidably disposed in respective oppositelyarranged, coaxially aligned actuating cylinders 45 and 46 disposed onopposite sides of the contact arm 30. Each of the cylinders 45 and 46may contain a light compression spring 50 disposed in an atmosphericchamber 5| at one side of the respective piston 4| or 43, which springis arranged to urge said piston toward its repose position in which itis shown in the. drawing in contact with a shoulder 52 formed in thecasing. In each of the cylinders 45, 46 at the opposite side of therespective pistons 4| and 43 there is a pressure chamber 55, which incylinder 45 is connected to a branch of the forward control pipe I00,and in cylinder device 46 is connected to a branch of the reversecontrol pipe 200.

In operation, with the engine crank shaft turning in its Forwarddirection, indicated by an arrow so titled in the drawing and with thecontact element 30 disposed in the position in which it is shown in thedrawing, with pipe 300 consequently connected to the reverse controlpipe 200 by way of the unseated valve 2, assume that fluid underpressure is supplied to the forward control pipe I00 while the reversecontrol pipe 200 remains vented to atmosphere. Such fluid under pressuresupplied to the forward control pipe I00 will flow to the pressurechamber 55 in the cylinder 45 and will cause, through movement of thepiston 4| and attached rod 40, resultant movement of the contact element30 into engagement with the teeth on gear 32 on the crank shaft rotatingin its Forward direction. So long as the crank shaft continues to turnin its Forward direction, the contact element 30 will be held againstfurther movement by rubbing contact with gear teeth 32. The effect ofpressure of fluid in the chamber 55 acting on the piston 4| will be keptjust sufiicient to maintain such rubbing contact, as an excessive forceof element 30 on gear teeth '32 is not desired from the standpoint ofwear and may be kept at a minimum through proper design of the spring 50for a given size piston 4| and for a given pressure of fluid. As soon asthe engine crank shaft, hence th gear 32,

4 I reverse direction of rotation, however, that is, from Forward toReverse in compliance w t the example, the teeth on gear 32 will mesh w't the teeth of the contact element 30 to cause piivotal movement of thearm 33 about pin 3| to th opposite side of said gear, whereupon spring31 will cause it to assume its opposite position in which the element 30is disposed away from th 35 teeth on gear 32 and in engagement with rod4 2 attached to piston 43 in its repose position in which it is shown inthe drawing, since chamber 55 in cylinder 46 is vented via the aheadcontrol pipe I00 at this time. Such pivotal movement of the arm 33 willcause shifting of cams I4 and I5 and thereby resultant closing of thevalve 2 and opening of the valve I for connecting the pipe 300 to thenow vented ahead control pipe I00 for reasons beyond the scope of thepresent invention.

Similarly, while the crank shaft is yet rotating in its Reversedirection, if fluid under pressure is supplied to the reverse controlpipe 200 while the forward control pipe I00 is vented, the piston 4| incylinder 45 will be returned by spring 50 to its repose position, whilefluid under pressure supplied to pipe 200 will flow to chamber 55 incylinder device 46 and cause the piston 43 to move the contact element30 into rubbing contact with the teeth on gear 32. As soon as the enginecrank shaft reverses its direction of rotation, that is from Reverse" toForward, the teeth on gear 32 will mesh with the teeth of element 30 tomove arm 32 to the opposite side of said shaft whereupon spring 31 willsnap it to its original position in which it is shown in the drawing,with said element 30 in contact with rod 40 attached to piston 4| in itsrepose position. As will be appreciated from previous description, thevalves and 2 will be positioned accordingly through resultant movementof links 34, 22 and cams I4 and I5.

In order to relieve shock and prevent undue wear of the two end teeth orserrations on element 30 which may result from rubbing engagement withthe teeth on member 32 said end teeth may be replaced by end teeth 10,referring to Fig. 2, which are pivotally connected to the element bymeans such as pins II and urged toward symmetrical relationship with theother teeth by such as leaf springs I2 in such a fashion that the teethI0 will act a pawls which will ride the teeth on the crank shaft in onedirection of its rotation and which will become effective to take holdwhen the crank shaft reverses its direction. The springs 12 may besecured by means of such as screws I3 to opposite sides of element 30and arranged to urge the teeth I0 toward engagement with respectiveshoulders I4 formed in said element to accommodate the teeth. Rubbingengagement of the tooth I0 at either side of element 30 with teeth onthe crank shaft will cause said tooth to leave shoulder I4 and pivotabout pin II against action of the respective spring I2, therebyreducing the impact effect between element and shaft, while matingengagement of the tooth 10 with teeth on said shaft will allow return ofsaid tooth into engagement with shoulder 14 to cause pivotal movement ofarm 33 to the opposie side of said shaft in fashion as aforedescribedherein.

In lieu of teeth or serrations either on the contact element 30 or onthe crank shaft or a gear associated therewith, the contact element maybe provided with a segmental shoe of resilient material, such as rubber,as shown in Fig. 3. The

- craink shaft Summary It will be seen that I have provided improvedmeans for conditioning such as valve mechanism comprised in directionsensing devices according to the direction of rotation of a reversiblee11 ,gine. l Having .now described the invention, what I claim as newdesire to secure by Letters Patentf-is:

1. Apparatusfor sensing direction of rotation of a reversiblerotatableshaft comprising in combination, apivotal element having a rest positionat either side of and out of contact with said shaft and being adaptedupon contact with said shaft to be moved thereby in the direction ofeither one or the other of said positions according to the direction ofrotation of said shaft, a piston arranged to be operated by fluid underpressure to move said element from one of said positions into contactwith said shaft, another piston arranged to be operated by fluid underpressure to move said element from the other of its positions intocontact with said shaft, an engine forward control pipe arranged toconvey fluid under pressure to and from said one piston, and an enginereverse control pipe for conveying fluid under pressure to and from saidother piston.

2. Apparatus for sensing direction of rotation of a reversible rotatableshaft, comprising in combination, an annular element associated withsaid crank shaft for rotation therewith and comprising gear-like teetharound its peripheral face, a pivoted element comprising a segmenthaving a series of gear-like teeth for intermeshing with the teeth ofsaid annular element for moving said pivoted element from either side ofsaid shaft in a direction toward a rest position at the opposite sideand out of contact with said annular element, means for moving saidpivoted element from either one of its rest positions into contact withsaid annular element, means carried by said pivoted element pivotallycarrying opposite end teeth of said series, said pivoted elementcomprising means for supporting said end teeth for driving said pivotedelement by said annular element only upon rotation of said annularelement in a. direction for moving said pivoted element from one side ofsaid crank shaft toward the opposite side.

3. Direction sensing apparatus comprising in combination with arotatable shaft, a contact element movable from either of two disengagedpositions at opposite sides of said shaft into engagement with saidshaft to be moved past said shaft by such engagement upon reversal indirection of shaft rotation, toggle spring means operatively connected.to said contact element to move said contact element to a respective oneof said disengaged positions after passing said shaft, and fluidpressure means operatively connected to said contact element to overcomeaction of said toggle spring means to effect said engagement.

4. Direction sensing apparatus comprising in combination with arotatable shaft, shaft gear teeth secured for rotation with said shaft,a contact element having rigidly attached corresponding gear teethmovable from either of two disengaged positions at opposite sides ofsaid shaft into rubbing engagement with said shaft gear teeth when saidshaft is rotating in one direction and movable pastsaid shaft by meshingengagement with said shaft gear teeth upon reversal in direction ofshaft rotation, toggle spring means operatively connected to saidcontact element to move same to a respective one of said disengagedpositions after passing said shaft, and fluid pressure means operativelyconnected to said contact element to overcome action of said togglespring means and effect said engagement.

5. Direction sensing apparatus comprising in combination with arotatable shaft, an annular element having serrations about itsperiphery and arranged for rotation with said shaft, a pivotal elementhaving serrations at one end for interlocking engagement with theserrations on said annular element for moving said pivotal element pastsaid shaft, toggle spring means operatively connected to said pivotalelement to move said pivotal element to a rest position free of saidshaft after passing same, and fluid pressure means operatively connectedto said pivotal element to move same against opposition of said togglespring means for effecting such engagement.

6. Direction sensing apparatus comprising in combination with arotatable shaft, a contact element having a resilient shoe movable fromeither of two disengaged positions at opposite sides of said shaft intoendwise engagement with said shaft for rolling movement past said shaftupon reversal in direction of shaft rotation, toggle spring meansoperatively connected to said contact element to move same to arespective one of said disengaged positions after passing said shaft,and fluid pressure means operatively connected to said contact elementto overcome action of said toggle spring means and effect saidengagement.

RALPH T. WHITNEY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 740,547 Fiske Oct. 6, 19031,748,307 Peters Feb. 25, 1930 2,042,915 Twist June 2, 1936 2,464,998Stevens Mar. 22, 1949

